To recover heat from fumes it is known to use pipes placed in the path of the fumes and in which a heat-carrying fluid circulates. Also, to cool or heat divided solids it has been proposed to entrain the solids in a gaseous current and make them pass over pipes in which a heat-carrying fluid circulates.
However, use of such pipes does not result in a very high heat exchange efficiency. Further, in the case where the fumes are charged with such substances as sulfates, sulfurous gases or sulfur dioxide, corrosion of the pipes may occur at certain temperatures. Further, the fumes which often contain dust and solid material in suspension, or gaseous currents that carry divided solids tend to clog the exchange pipes and abrade them so that the pipes must be cleaned or changed frequently.
This invention aims at remedying these drawbacks and in particular in providing a process for recovering heat exhibiting a clearly higher efficiency and a process that avoids the phenomena of corrosion of the pipe and their clogging.
It also aims at providing a process making it possible to simultaneously clean the fumes.